1. Field of the Invention
The present invention pertains to the field of digital communications. More particularly, this invention relates to a system for inverse multiplexing data transmission over multiple communication links in an asynchronous transfer mode communication network.
2. Background
Packet switching communication networks are commonly employed to transfer digital information over long distances. Such packet switching communication networks are also referred to as cell switching communication networks. One type of packet switching communication network is an asynchronous transfer mode communication network. An asynchronous transfer mode communication network enables the transfer of digital voice information, digital video information and digital data over short or long distances via common carrier communication links. Such a communication network enables a wide variety of communication devices to share common carrier communication links on a demand driven basis. For example, such asynchronous transfer mode communication networks are commonly employed for a wide area network (WAN) communication.
The common carrier communication links employed in such asynchronous transfer mode communication networks typically include relatively low speed metal wire based communication links. One such type of relatively low speed common carrier communication link available in North America is the T1 communication link. A typical T1 communication link provides a maximum data rate of 1.544 megabits per second. Similarly, the E1 common carrier communication links available in Europe provide a relatively low maximum data rate of 2.048 megabits per second.
In addition, the common carrier communication links employed in such asynchronous transfer mode communication networks usually include higher speed optical based communication links. An example of such a high speed common carrier communication link available in North America is the T3 communication link which provides a maximum data rate of 45 megabits per second. An example of a high speed common carrier communication link available in Europe is the E3 communication link which provides a maximum data rate of 34 megabits per second.
Prior asynchronous transfer mode communication networks that require high bandwidth communication links typically employ T3 or E3 communication links rather than the lower speed T1 or E1 communication links. Unfortunately, the subscription rates for such T3 common carrier communication links are usually much higher than the subscription rates for T1 or E1 links. Moreover, in North America such T3 common carrier communication links are not as widely available as T1 common carrier communication links. Worse yet, in Europe E3 common carrier communication links are rarely available and E1 common carrier communication links have only recently become widely available.
As a consequence, communication services requiring such high bandwidth communication links typically require a high premium payment for such high speed common carrier communication links. Moreover, such required high speed communication links may not be available in some areas for such an asynchronous transfer mode communication network.
In addition, some prior asynchronous transfer mode communication networks require communication links with a bandwidth higher than is provided by low speed common carrier communication links such as T1 or E1 but do not require the high bandwidth of the T3 or E3 common carrier communication links. Unfortunately, communication services requiring such medium level bandwidth communication links must typically employ expensive high speed common carrier communication links even though the full bandwidth range is not needed. For example, an asynchronous transfer mode communication network requiring a maximum data rate of 10 or 20 megabits per second must usually employ high speed T3 or E3 common carrier communication links. Such high speed common carrier links unnecessarily increase the cost of communication for subscribers to such an asynchronous transfer mode communication networks.